Fire in the Seasonal Semideciduous Forest: Impact and Regeneration at Forest Edges

background

This study looks at a fragment of semi-deciduous forest in Brazil to determine the effects of fire on vegetation at varying distances from the fragment’s edge, as well as the recovery of forest structure and species diversity after fire.

Research Goals & Methods

Five transects (10m x 50m) were established from the edge to the forest interior in an area of forest which was burned as well as a nearby unburned forest, with plots grouped into two strips depending on their distance from the forest edge – 0-20m (external) and 20-50m(internal). In the burned section of forest, data were collected at 6, 15, and 24 months following the fire.

Conclusions & Takeaways

In both the internal and external strips, forest structure and species composition of the burned forest differed significantly than that of the unburned forest, with the most damage recorded at distances closest to the edge. Within the internal strip of the burned forest, 89% of the basal area was estimated to have been lost, and 100% was lost in the external strip. Forest recovery also varied with distance to the edge and with the species, with faster recovery observed further from the edge. After 24 months, the burned forest sector had yet to reach the same level of biomass or species diversity as the unburned sector. Of the 77 species sampled in the unburned sector, 43 were not sampled in the burned forest. Extrapolating from the rate of basal area increase, the authors predict that it would take 5 years to recuperate the basal area to pre-fire levels in the internal strip and 11 years in the external stip. The authors predict that the observed results occur because of the rapid proliferation of grasses and vines after a fire, especially near the forest edge, which hinders tree regeneration.